The invention relates generally to the area of electrical components. More specifically, the invention relates to the area of reliability of electrical components such as electrical switches and electrical switch arrays.
Micro-electro-mechanical systems (MEMS) represent an integration of mechanical elements, with electrical elements on a substrate through micro-fabrication technology. While the electrical elements are typically fabricated using integrated circuit fabrication processes, the mechanical components are typically fabricated using compatible micromachining processes, such as lithographic, metallization, or etching processes. The ability to employ such processes is a key advantage of MEMS fabrication technology as it allows for enhanced control of the characteristic “micro-scale” dimensions typical of MEMS devices. Such processes also enable efficient production of MEMS devices by enabling batch fabrication of the MEMS devices on a common substrate die.
MEMS technology is suited to fabricate components, such as actuators or switches, that require a limited range of motion for their operation. Switch arrays may also be realized based on MEMS technology.
One type of MEMS includes a suspended connecting member, which connecting member may be in the form of a movable beam, such as a cantilever. Such a device may further include an actuation mechanism, which actuation mechanism may be electrostatic, to cause a movement of the suspended connecting member. The movement enables an electrical communication between any two or more parts of the MEMS by causing a “making” and “breaking” of an electrical contact between a surface of the suspended connecting member and a surface of an adjacent part of the MEMS.
Unacceptably high voltages can develop across a MEMS switch array when the MEMS switch array “opens” from an energized state. The development of such voltages can result in arcing between electrical contacts of the individual switches of the switch array. Therefore, an issue affecting reliability of performance of a MEMS switch array concerns the possibility of arcing between, or welding of, the two components under question during the opening. This arcing and/or welding may result in uncontrolled variation in the electrical contact resistance, and indeed, may also result in temporary or permanent seizure of any one or more electrical contacts. Development of reliable and cost-effective MEMS and MEMS arrays is one of the challenges facing MEMS technology. High reliability MEMS and MEMS arrays would therefore, be highly desirable.